C1253

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1252/52, C1253/53: Brake Booster Pump Motor on Time Abnormally Long


DESCRIPTION

The skid control ECU detects decreases in the accumulator pressure according to the data from the accumulator pressure sensor, and then starts and stops the pump motor by operating the motor relay.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When replacing the brake booster with master cylinder (skid control ECU or brake actuator), perform initialization and calibration of the linear solenoid valve Initialization.

PROCEDURE

1. PERFORM ACTIVE TEST USING TECHSTREAM (ABS MOTOR RELAY)

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Select the Active Test on the Techstream Data List / Active Test.

ABS/VSC/TRAC





*: Electronically Controlled Brake System

(d) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





*: Electronically Controlled Brake System

(e) Check the operating condition of the ABS motor relay when operating it using the Techstream.

Result:





B -- INSPECT SKID CONTROL ECU (MRI TERMINAL)
A -- Continue to next step.

2. INSPECT BRAKE BOOSTER PUMP

(a) Turn the power switch off.





(b) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

(c) Disconnect the brake booster pump connectors.

(d) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





Text in Illustration





NG -- REPLACE BRAKE BOOSTER PUMP Removal
OK -- Continue to next step.

3. INSPECT BRAKE BOOSTER PUMP (GND TERMINAL)

(a) Measure the resistance according to the value(s) in the table below.





Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.

4. READ VALUE USING TECHSTREAM (ACCUMULATOR PRESSURE SENSOR)

(a) Reconnect the brake booster pump connectors.

(b) Connect the Techstream to the DLC3.

(c) Turn the power switch on (IG).

(d) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(e) Wait for 30 seconds without depressing the brake pedal.

(f) Check that the accumulator pressure sensor output values change is within the specified range.

OK:

Accumulator pressure sensor output values change is within 0.55 V.

NG -- PERFORM ACTIVE TEST USING TECHSTREAM (SOLENOID VALVE)
OK -- Continue to next step.

5. RECONFIRM DTC

(a) Turn the power switch off.

(b) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the power switch on (IG).

(d) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal

A -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting

6. INSPECT SKID CONTROL ECU (MRI TERMINAL)

(a) Turn the power switch off.





(b) Check that the ABS MTR1 (30 A) and ABS MTR2 (30 A) fuses are normal.

(c) Make sure that there is no looseness at the locking part and the connecting part of the connector.

(d) Disconnect the skid control ECU connector.

(e) Measure the voltage according to the value(s) in the table below.

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (MRI CIRCUIT)
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - BRAKE BOOSTER PUMP)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.

(b) Disconnect the brake booster pump connectors.

(c) Measure the resistance according to the value(s) in the table below.

Standard Resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR

OK -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal

8. PERFORM ACTIVE TEST USING TECHSTREAM (SOLENOID VALVE)

(a) Select the Active Test on the Techstream Data List / Active Test.

HINT
The Active Test can be performed when the following conditions are met.

- ABS main relay is on.
- Park (P) is selected.
- Parking brake is applied.
- Vehicle speed is 0 km/h (0 mph).

ABS/VSC/TRAC





*: Electronically Controlled Brake System

(b) Perform the Active Test of the solenoid using the Techstream.

(c) Select the Data List on the Techstream Data List / Active Test.

ABS/VSC/TRAC





(d) Check that the output value of the wheel cylinder does not increase.

OK:

The output value of the wheel cylinder does not increase.

HINT
If any output value increases, there may be brake fluid leaks in the brake actuator.

NG -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal

OK -- REPLACE BRAKE BOOSTER PUMP Removal